Testing apparatus



Sept. 18, 1934. s. LEIBOFF TESTING APPARATUS Original Filed July 20,1929 INVENTOR'.

5; ATTORNEY Patented Sept. 18, 1934 :PATENT; OF- F ICE .TESTINGAPPARATUS Samuel Leo Leiboff, Bronx, N. Y.

Application July'20, 1929, SerialNo. 379,708

;Renewed- November 3, 1933 3 Claims.

The invention relates to testing apparatus, such as apparatus for thedetermination of urea in the blood, and the like purposes.

An object of this invention is to provide ap- 5 paratus of the characterdescribed adapted for the usual routine work whereby the amount of ureain blood may be accurately determined without complicated apparatus suchas autoclaves or distillation apparatus such as is usually necessary forcarrying out such determinations by the high pressure method and othermethods now in use.

Another object of this invention is to provide in an apparatus of thecharacter described, an improved, simple, cheap and highly efiicient andpractical device for containing substances raised to high pressures byheat, and which device is automatically sealed upon heating thesubstances there within without necessitating additional 5120 clampingmeans.

A further object of this invention is to provide improved means forsimultaneously carrying out a number of tests requiring the heating ofliquids under pressure.

A still further object of the invention is to pro-- -vide-a neat, ruggedand compact apparatus of the character described which shall becomparaytively cheap to manufacture, comprise fewand simple parts, beeasy to manipulate and practi-.

cal and efficient to a high degree.

Other objects of this invention will in part be obvious and in parthereinafter pointed out.

The invention accordingly consists in the features of construction,combinations of elements, and arrangement of parts which will beexemplified in the construction hereinafter described, and of which thescope of application will be indicated in the following claims.

In the accompanying drawing in which is. shown one of the variouspossible illustrative embodiments of this invention,

Fig. 1 is aside, elevational view partially in cross-section of anapparatus embodying the invention, with parts broken away to show theinterior construction; and

Fig. 2 is a cross-sectional view taken on line 2- -2 of Fig. 1.

Referring now in detailto the drawing, 10 designates an apparatusembodying the invention ...50 particularly adapted for use in thedetermination of urea nitrogen in the blood. There are now in useseveral methods for determining the urea nitrogen content in the blood,such as the so-called low pressure method employing urease, in which.-.55 the ammonia is either distilled or aerated into an -.methodemploying autoclaves.

1 of metal, such as copper. within said. beaker. 21 is a rack 22 havinga base tached to said tube 25 is a disc 28 made of copper turned.

acid medium; and the so-called high pressure I Both of these methods,.as carried out heretofore, have been found to be cumbersome and quitetime consuming. Furthermore, the lowpressure method hasten been found togive somewhat inaccurate results, and, the high pressure method has theadded objection that a special autoclave is required to obtain thehigher temperatures.

The apparatus 10, herein described in detail as. an illustrativeembodiment of this invention, substantially eliminates theseobjectionable features. Said apparatus may comprise a stanchion 11having a base portion 12 and upstanding rod 14. A

clamp 15 may be adjustably secured to said r0d:;70 14 in any desiredadjustable position as by actuating the thumb screw limounted in a lug18 integrally formedwith said clamp. Said clamp 15 is further formedwith an integral arm 19 and an annular ringzportion 20. Dependinglysupported '7 within said ring 20 is apbeaker 21 preferably madeRemovably, received 23 .adapted to rest on the lower wall or bottom2410f said beaker. Said rack further comprises .anupstanding, elongatedmetal tube 25 made of .copper,1or. the like metal toprevent breakage.

.Said tube. 25 acts as. a protecting jacket for a The thermometer. 26 ispreferably; graduated to 1-200 C; At substantially the mid-portion.thereofor below the cut outgportion 27 and ator similar metal, saiddisc being formed with a pluralityof spaced radial notches 29., Theouter edge portions 30 of said disc between said notches,

are preferably slightly rounded upwardly or, up-

Suspended from saiddisc 28 in a manner hererinafterappearing are aplurality of glass pressuretubes 31. Each of said tubes 31 comprises anelongated tubular portion 32 having prefer- ..ably, a rounded bottom33a. At its top, each of said tubes; 31 is formed .withan inwardlyflaring portion 33 and. an outwardlyfiaring portion 34,

:thus providing a constricted neck 35. vThe inner inwardly flaringportion 33. The outer surface 43 of said head 42 is preferably ground sothat when contacting the ground surface 36 of the tube, a substantiallytight or leak-proof seal will be effected. Adjacent the upper endthereof, said stopper is formed with a plurality of spaced heads 44,respectively, separated by a neck portion 46. As clearly shown in Fig.1, the neck portion 46 of said member 40 is received within the notch 29and is suspended from said disc 28 since the head 45 thereof contactsthe adjacent portions of the disc. The upturned portions 30 prevent thestopper from sliding off the disc. The outer diameter of the tubularportion 41 is smaller than the inner portion of the neck 35, so that thetube 31 may be lifted to permit the insertion of liquids and the likesubstances into the tube. It will be noted that upon lifting the tube 31when suspended with the head 42 of member 40 tightly wedged against theneck 35 of the tube, the disc 28' will strike the head 44 and causedisengagement of said head to allow relative movement between said tube31 and stopper member 40. Mounted on said base 12 is a Bunsen burner 39.The tube 31 as well as the stopper member 40 are preferably made ofheavy Pyrex glass to withstand high pressures and temperatures.

One illustrated method of carrying out a test with the apparatusdescribed above will now be described. For determining the urea contentof blood, a tube 31 may be suspended from the disc 28, the entire rack22 however, being removed from the beaker and placedon a table. The tube31 is then raised to bring the stopper member 40 further into the tubeand permit the insertion of liquid into said tube. 5 c. c. of a fil--trate containing the water-soluble substances of the blood dissolved inwater-known as Folin-Wu filtrate-and other reagents are now introducedinto the tube by holding a tip of the pipette close to the lower end orhead 42 of the stopper. That portion of the stopper may be washed downwith 1 c. c. of water followed by 1 c. c. of normal sulphuric acid. Thetube'may then be closed by lowering the same. The rack with the tube insuspension is then placed in'the beaker and an oil bath introduced intosaid beaker at such level that the liquid in the tube is somewhat belowthe level in the oil. Any oil of high boiling point will do. Nujol hasbeen found to serve the purpose well as it produces very little odorwhen heated. The oil bath is then heated by means i of the Bunsen burner39, to a temperature between 145 and 155 C., the steam will wedge thestopper head 42 tighter against the inner surface 36 of the tube. Thehigher the temperature, the greater will be the pressure within thetube, and the better the seal produced. Since the tube is made of Pyrexglass, high pressures and temperatures can be easily withstood withoutbreakage or damage to the apparatus.

After the oil has been kept at about 150 C.

for about ten minutes, the tube is removed from the oil bath. Whencooled, the stopper is released by pushing it further into the tube, andpreferably 15 c. c. of water added followed by 3 c. c. Nessler solution.Water is then added to the 25 c. 0. mark and the tube shakento mix thecontents. The quantity of urea may then be quickly and accuratelydetermined by comparing the resulting solution in a colorimeter with astandard solution of ammonium sulphate. Thus a very simple, quick andaccurate method of determining urea in the blood is provided.

The tube 31 and stopper member 40 may have a great number of uses otherthan that described for urea determination, wherever substances are tobe heated under increased pressure. The particular construction of thestopper having a head within the tube and the constricted inwardlyflaring neck portion adapted to receive said head automatically producea tight seal upon increase of pressure within the tube.

With the apparatus shown, as many as six tests may be carried outsimultaneously.

' It will thus be seen that there is provided a device in which theseveral objects of this invention are achieved, and which is welladapted to meet the conditions of practical use.

As various possible embodiments might bemade of the above invention, andas various changes might be made in the embodiment above set forth, itis to be understood that all matter here-;;

in set forth or shown in the accompanying drawing is to be interpretedas illustrative and not in a limiting sense.

Having thus described my invention, I claim as new and desire to secureby Letters Patent:-

1. In combination, a tube having an inwardly flaring portion adjacentthe top and an outwardly flaring portion extending from the inwardlyflaring portion to provide a constricted neck, a stopper having astraight portion extending through, said neck and terminating at thelower end thereof in a conical shaped head contacting the inner surfaceof said inwardly flaring portion, said stopper being formed with aplurality of spaced heads adjacent the upper end thereof separated by aneck portion.

2. In combination, a tube having an inwardly fiaring portion adjacentthe top and an outwardly flaring portion extending from the inwardlyflaring portion to provide a constricted neck, a stopper having astraight portion extending through said neck and terminating at thelower end thereof in a conical shaped head contacting the inner surfaceof said inwardly flaring portion, said stopper being formed with aplurality of spaced heads adjacent the upper end thereof separated by aneck portion, the inner surface of said inwardly flaring portion and theouter surface of said conical head being ground.

3. In combination with a receptacle having a constricted neck, meanseffective upon increase of pressure within said receptacle for formingaseal therefor, said means comprising an elongated rod slidably extendingthrough the opening in said neck and having an" enlargedhead at thebottom end thereof engaging said neck, said rod having a pair of spaced,enlarged portions on the upper end thereof, and .rn'ean's for suspendingsaid receptacle comprising a stanchion, and a member on said stanchionhavinga. notch receiving the portion of the rod .between said spaced,enlarged portions.

SAMUEL' LEO LEIBOFF.

